Polycycloolefin amorphous polymers (COP) and cycloolefin/acyclic olefin amorphous copolymers (COC) are known in the art and noteworthy for their superior transparency, barrier properties, chemical stability, solvent resistance and chemical purity. These materials are prepared as shown in Scheme I below:

Cyclic olefin copolymers (COC) in particular are versatile transparent polymeric materials. The lack of mechanical durability or toughness in some aspects of COCs and COPs, especially brittleness (as opposed to ductility) has somewhat limited adoption of the material in some applications. Imparting additional durability into cycloolefin containing material without significantly compromising transparency and chemical purity has proven to be very difficult. Improving durability of COCs with respect to impact resistance, flexibility, and tear resistance is essential for this material to satisfy performance demands for new, challenging applications. Injection molding applications include durable and non-disposable medical devices, large capacity vials, cartridges and bottles, labware, and diagnostics. Injection blow molding and injection stretch blow molding can be used to make large size medical and consumer goods containers and housewares. Numerous attempts have been made to improve mechanical durability of cycloolefin compositions; however, recycle characteristics, transparency, and chemical purity have been particularly difficult to maintain while improving, for instance, impact resistance. See, for example, U.S. Pat. No. 5,438,093 to Stricharczuk et al., which discloses modified polycycloolefins including flame retardants, elastomer impact modifiers, fillers and so forth. See Col 7, lines 65, through Col. 10, line 33. One specific approach to providing more impact resistance to cycloolefin polymer compositions suggested in the art is to incorporate core/shell elastomers. See U.S. Pat. No. 6,683,134 to Miyamoto et al. as well as U.S. Pat. No. 5,574,100 to Sagane et al. Such compositions raise recycling issues as with other non-olefin components, discussed below.
U.S. Pat. No. 5,278,214 to Moriya et al. also discloses impact-modified cycloolefin based polymer compositions. These compositions generally include a specific cycloolefin-based polymer, a graft-modified elastomer and an amino compound which is reported to increase impact strength and gloss. See Col. 18. In addition to other components, the compositions may include additives such as an inorganic filler, an organic filler, a thermal stabilizer, a weathering stabilizer, an antistatic agent, an anti-slipping agent, an antiblocking agent, an anti-fogging agent, a lubricant, a pigment, a dye, natural oil, synthetic oil, wax, etc.
The following references disclose the use of Kraton styrene block copolymer elastomers in connection with cycloolefin copolymers:    U.S. Pat. No. 7,365,130, issued Apr. 29, 2008, entitled “Cycloolefinic Copolymer for High Modulus Film”, to Rivett et al.;    U.S. Pat. No. 7,267,855, issued Sep. 11, 2007, entitled “Articles Prepared From Hydrogenated Controlled Distribution Block Copolymers”, to Handlin, Jr. et al.;    U.S. Pat. No. 6,544,610, issued Apr. 8, 2003, entitled “Container and Blow-Molded Product”, to Minami et al.;    U.S. Pat. No. 6,090,888, issued Jul. 18, 2000, entitled “Cyclic Olefin Polymer Blends Exhibiting Improved Impact Resistance and Good Transparency”, to Khanarian et al.;    U.S. Pat. No. 4,918,133, issued Apr. 17, 1990, entitled “Cycloolefin Type Random Copolymer Compositions”, to Moriya et al.;    U.S. Pat. No. 4,418,178, issued Nov. 29, 1983, entitled “Impact Modified Polymers of Cycloolefins”, to DeWitt;    U.S. Pat. No. 4,166,083, issued Aug. 28, 1979, entitled “Rubber Composition and Process for Preparation Thereof”, to Ueda et al.;    United States Patent Application Publication No. US 2008/0300363, published Dec. 4, 2008, entitled “Blends of Co-Precipitated Hydrogenated Ethylene-Dicyclpentadiene and Elastomeric Polymers to Provide Impact Modified Structural Polyolefins”, of Baugh et al.;    U.S. Patent Application Publication No. US 2008/0033112, published Feb. 7, 2008, entitled “Polymer Compositions Comprising Cyclic Olefin Copolymers and Polyolefin Modifiers”, of Squire et al.; and    U.S. Patent Application Publication No. US 2007/0037927, published Feb. 15, 2007, entitled “Compatibilized Blends of ABS Copolymer and Polyolefin”, of Yang.
U.S. Pat. No. 5,569,711 to Yamamoto et al. discloses cycloolefin resin compositions with elastomers and polyamides. The compositions are reported to have improved impact and grease resistance. See Cols. 33-34. See, also, U.S. Pat. Nos. 5,585,433 and 5,439,973 also to Yamamoto et al. The use of a polyamide negatively impacts recycle characteristics and introduces additional chemistry into the system.
U.S. Pat. No. 5,567,777 to Tsuji et al. discloses modified cycloolefin copolymers prepared with elastomer components which are reported to have improved impact resistance, strength and transparency. The process appears somewhat complex as are the compositions. See, also, U.S. Pat. No. 5,567,776, also to Tsuji et al. See, also, U.S. Pat. No. 5,494,969 to Abe et al. which discloses another resin composition wherein a cycloolefin resin is prepared in the presence of a cycloolefin elastomer.
United States Patent Application Publication No. US 2005/0014898 of Kanai discloses still another copolymer composition including a cycloolefin. There is provided in accordance with this publication a cyclic olefin based resin composition which includes: a cyclic olefin based resin (A); a modified cyclic olefin based resin (B) prepared by grafting and/or copolymerizing an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride to the cyclic olefin based resin (A); an olefinic elastomer (C); and a modified polyolefin (D) having an epoxy group, and in which a weight ratio of the component A to the component B, i.e. A/B, is in the range of 98/2 to 2/98, a weight ratio of the component C to the component D, i.e. C/D, is in the range of 98/2 to 2/98, and a ratio of the total weight of components A and B to the total weight of components C and D, i.e. (A+B)/(C+D), is in the range of 95/5 to 50/50. Here, again, preparing the composition is relatively complex. See, also, U.S. Pat. No. 4,874,808 to Minami et al. and U.S. Pat. No. 7,026,401 to Osan et al. as well as Japanese Patent Publication JP 5271484.
It has been unexpectedly found in accordance with the present invention that partially crystalline cyclic olefin elastomers impart toughness or durability as seen in connection with ductility and impact resistance to brittle cycloolefin containing polymers, regardless of norbornene content, i.e. having a glass transition temperature in the range, for example, of 33° C. to 200° C., while maintaining superior optical properties and/or appearance of molded articles. Durable cyclolefin containing compositions can be extruded into thin and heavy gauge sheeting for thermoforming trays, containers, and so forth. Durable cycloolefin films can be used alone or coextruded with other polymers, especially polyolefins, to satisfy growing sustainably and resource conservation requirements for new flexible packaging applications, such as bags, pouches, forming films, and form-fill-and-seal films and the like.
Details of the invention will be appreciated from the discussion hereinafter provided.